The present invention relates to a combustion chamber for an aircraft turbojet engine having a heat protecting lining on the interior of the wall bounding the combustion chamber. The lining comprises a plurality of insulating tiles having a unique juncture to avoid large thermal gradients along the length of the combustion chamber, the juncture also facilitating the formation of a cooling air layer along the inner surfaces of the tiles.
Turbojet engines for civilian and military aircraft have ever increasing power outputs. One of the many factors involved in such increased output has been the higher compression ratios of the intake air. One of the results of the use of such higher compression ratios has been the increase in gas temperatures both at the compressor outlet and within the confines of the combustion chamber. In order to preserve the structural integrity of the combustion chambers, means must be utilized to protect the walls bounding the combustion chambers. However, the amount of air used to establish cooling films on the inner surfaces of the combustion chamber walls must be kept to a minimum in order to maintain the efficiency of the engine.
It is known to utilize insulating tiles in the combustion chamber to minimize the heat transfer between the gases within the combustion chamber and the wall bounding the combustion chamber. French Patent 2,567,250 and British Patent 2,172,987 disclose combustion chamber configurations in which the combustion chamber has a structural wall extending between the intake and the outlet of the combustion chamber with annular rings of insulating material spaced from the inner surface of the wall between the wall and the combustion chamber. The junctures of the longitudinally adjacent insulating ring define outlets through which cooling air passes to establish a cooling film on the inner surface of the insulating rings. While generally successful, these configurations form rather steep thermal gradients between longitudinally adjacent insulating rings.
French Patent 2,644,209 describes a protective lining for an afterburner duct which comprises a plurality of tiles affixed to and spaced from the duct. A seal is interposed between longitudinally adjacent rows of tiles.